Quality of care can be measured by assessing the structure, process, or outcomes of care. However, elements of care processes do not signify quality until their relationship to desirable outcomes has been established. In pediatrics, there are few studies examining the process-outcome link secondary to small sample sizes of patients with any particular condition and the rare occurrence of readily measured outcomes (e.g. death). As a result, most pediatric practice guidelines include recommendations based on expert consensus opinion rather than scientific evidence establishing a link between the recommended care processes and outcomes. In many cases, we assume that providing care consistent with these guidelines will result in better outcomes. Under funding from the National Heart Lung Blood Institute, we have developed and pilot tested a rigorously designed quality of care assessment tool, the Pediatric Respiratory Illness Inpatient Measurement System (PRIMES). PRIMES is a quality measurement tool that is structured to generate quality scores using medical records data for five respiratory conditions: asthma, bronchiolitis, croup, community acquired pneumonia, and cystic fibrosis pulmonary exacerbation. The tool assesses processes of care provided in the pediatric emergency department (ED) and inpatient settings and its content is largely based on established expert consensus practice guidelines. We propose to conduct an outcome validation study of PRIMES by assessing the relationship between level of adherence to the processes of care included in the tool, improved outcomes, and costs of care. Using PRIMES, we will conduct a detailed assessment of the hospital management of 3,000 patients admitted to one of five United States children's hospitals belonging to the Pediatric Research in Inpatient Settings (PRIS) Network. We will assess improvements in health related quality of life (HRQOL) using a validated survey measure at three time points: the month prior to the index admission (baseline), the day of admission, and two weeks after discharge. We will also assess costs of care for the index ED visit and hospital admission as well as length of stay (LOS), 30-day return ED visits, and readmissions. The proposed study will substantially add to our understanding of the relationship between adhering to recommended standards of care in pediatrics and health care outcomes. If found to predict important outcomes, PRIMES could be used to both identify areas of respiratory illness care where quality improvement efforts are most needed and provide valid performance comparisons across hospitals caring for children nationally.